Verifying the identity of a person or group of people, referred to as authentication, has many uses in the context of computing. People often have multiple user accounts—accounts in the operating systems of their computing devices, accounts with social networking sites, accounts with online retailers, and so on—that employ some type of authentication before access to the account is granted. In many cases, these accounts are configured to authenticate a user depending on whether the user provides a correct username and password combination. If the user provides a correct username and password, access to account resources is granted. If the user does not provide a correct username and password, access to account resources is denied.